Benthic Macroinvertebrate Survey

Benthic Macroinvertebrate Survey Aquatic Assessment Ecological Assessment

Biological Systems consultants scientists collect benthic macroinvertebrate samples  according to the local regulatory authority protocols: the typical sampling protocol for a riffle sample in a Kentucky headwater stream is as follows as described in the Kentucky Division of Water (KDOW) Standard Operating Procedure (SOP) manual:

1. Four 0.25 m2 quadrat kick net samples are collected within the thalweg of cobble/boulder
riffle habitat. This habitat is targeted to ensure the highest species richness and
abundance of benthic macroinvertebrates. The thalweg of a riffle also guarantees the
most flow permanence and substrate stability in these often intermittent streams.

2. Two kick net samples are allocated to each of two distinct riffles (at minimum) that are
separated by at least one pool or run. This is done to help reduce between-riffle
variability. However, if there are several riffles located within the reach, the sampling
effort should be spread across the reach to give a comprehensive evaluation of the entire

3. The four samples are composited into a 600 μm mesh wash bucket to yield a 1m2 semiquantitative

4. The composited sample is partially field processed using a U.S. No. 30 sieve (600 μm)
and wash bucket.

5. Large stones, leaves and sticks are individually rinsed and inspected for organisms and
then discarded.

6. Small stones and sediment are removed by elutriation using the wash bucket and U.S.
No. 30 sieve.

7. The contents of the cleaned wash bucket are placed into a glass, sample jar with 95%

8. The wash bucket will be picked clean of any remaining macroinvertebrates.

9. The sample jar will be labeled with the appropriate information  and will
be ready for transport to the lab for analysis.

Analysis and identification is performed by our staff aquatic entomologist.

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